<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <link rel="stylesheet" href="style.css">
    <title>black and white</title>
</head>
<body>
<fieldset>
    <div class="theme-switch" style="width: 100px;height: 30px;background-color:cadetblue; border-radius: 15px; display: flex;justify-content: center;align-items: center;">
        <input type="radio" name="theme" value="light" id="light" checked><label for="light">白</label>
        <input type="radio" name="theme" value="dark" id="dark"><label for="dark">黑</label>
    </div>
</fieldset>
<h1>前端侦探</h1>
</body>
</html>